November 3, 2014 – Hosk's Dynamic Blog

Javascript is a slippery beast, Slave to no one and master to many. It’s just a quick blog post today, not as quick as this article I found written by me

CRM 2011 – Javascript snippet – How to remove all existing values from an OptionSet

I’m more happy in the .net and C# world with it’s static variables.

What I mean by this is C# you have to declare the variable you are going to use e.g.

string
int
bool
custom type

but with Javascript a var can be anything, it’s like something out of X-men changing and morphing it’s way along.

Here is a good article about static and dynamic languages

Static vs. dynamic typing of programming languages

Why doesn’t Hosk like Dynamic Javascript

Good question, surely I should like dynamic things.

Some of the reasons I don’t like it are

Hard to read/understand other peoples code
Bugs can be compiled and then appear in runtime when the code is run
It encourages the cowboy coders to go to town
It’s strange and different

Get to the point

I’m not saying I don’t like Javascript it’s just sometimes I want to do things and I’m not sure HOW because the syntax can be a bit crazy. Like all developers once we have a working example in our hands, we are off. So recently I saw some interesting Javascript in a project I am working and I was intrigued to understand how it worked and use it again.

One cool feature about Javascript is the ability to pass in function names using variables, a bit like reflection(ish), but only once you know how because I tried searching for this on the internet and fell down a big dark hole.

Example

On a form I have 4 OptionSets which we are dynamically setting the values to.

If I pass in the OptionSetField name I can dynamically get the control


var control = Xrm .Page .getControl (OptionSetFieldName);

I can then clear this control


control. clearOptions();

I can then add in the new values and build it up. The beauty of dynamic code is I can use the same code for all the OptionSets because I can pass in the name of the control.

When adding a the new optionSet values in, I can use a dynamic variable to retrieve the field name from array, which contains values retrieved from a fetchXML query. The childField is the name of the field in CRM.


      var option = {
                    value: retrievedOptionSet[i]. text == "" ? "null" : retrievedOptionSet[0].attributes [childField]. value,
                    text: retrievedOptionSet[0].attributes [childField]. formattedValue
                };
                control. addOption(option);
            }

Summary

It may be common knowledge to all you JavaScript wizards out there, but I hadn’t used or seen JavaScript using dynamic names. It makes sense and it’s very useful so I thought I would share it with you